Substance P-saporin down-regulates substance P receptor immunoreactive sensory dorsal root ganglion neurons innervating the lumbar intervertebral discs in rats
Substance P-saporin down-regulates substance P receptor immunoreactive sensory dorsal root ganglion neurons innervating the lumbar intervertebral discs in rats
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DOI：
10.1097/01.brs.0000250306.12996.fa
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发表时间：
2006-12-15
期刊：
影响因子：
3
通讯作者：
Takahashi, Kazuhisa
中科院分区：
文献类型：
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作者：
Ohtori, Seiji;Inoue, Gen;Takahashi, Kazuhisa
研究设计.应用免疫组织化学和逆行神经示踪技术研究大鼠腰椎间盘背根神经节细胞P物质受体的变化。我们评估了椎间盘内注射P物质-皂草素（一种对表达P物质受体的细胞有选择性的毒素）的效果。大鼠L5/6椎间盘由L1-L 6背根神经节多节段神经支配。P物质和神经激肽-1受体参与炎性疼痛传递。P物质免疫反应的感觉神经纤维在人类椎间盘和免疫反应的背根神经节神经元支配大鼠椎间盘已被报道是重要的椎间盘源性腰痛的传输。在目前的研究中，我们评估了椎间盘内注射P物质-皂草素（一种对表达P物质受体的细胞具有选择性的毒素）的效果。16只大鼠（对照组，n = 8; P物质-皂草素组，n = 8）。为了检测支配L5/6椎间盘的背根神经节神经元，将神经示踪剂（荧光金晶体）放置到椎间盘中。在施加荧光金7天后，暴露L5/6椎间盘并注射175 ng无菌物质P-皂草素（P-皂草素组，n = 8）。第一次手术后14天，收获每个背根神经节，切片，并使用兔神经激肽-1抗体进行神经激肽-1免疫组织化学处理。分别计数两组荧光金标记神经元、荧光金标记神经元和神经激肽1免疫阳性神经元的数量。荧光金逆行标记的L5/6椎间盘神经元分布于两组L1 ~ L 6背根神经节。在荧光金标记的神经元中，对照组神经激肽1免疫反应阳性神经元的比例为35%。而P物质皂草素组椎间盘内神经激肽1免疫反应阳性神经元的比例为8%。P-saporin物质可显著降低神经激肽1免疫反应阳性神经元的比例。P物质皂草素降低神经激肽-1免疫反应阳性神经元的比例，支配与椎间盘源性腰痛有关的椎间盘。Psaporin物质可能是研究椎间盘源性下腰痛发病机制的有用工具。
Study Design. To examine changes in substance P receptors on dorsal root ganglion cells innervating the rat lumbar intervertebral discs using immunohistochemistry and a retrograde neurotracing method.Objective. We evaluated the effects of intradiscal administration of substance P-saporin, a toxin selective for cells expressing substance P receptors.Summary of Background Data. The rat L5/6 intervertebral disc is multi-segmentally innervated from the L1-L6 dorsal root ganglions. Substance P and the neurokinin-1 receptor contribute to inflammatory pain transmission. Substance P immunoreactive-sensory nerve fibers in human intervertebral discs and immunoreactive-dorsal root ganglion neurons innervating rat intervertebral discs have been reported to be important in the transmission of discogenic low back pain. In the current study, we evaluated the effects of intradiscal administration of substance P-saporin, a toxin selective for cells expressing substance P receptor.Methods. Sixteen rats were used (control group, n = 8; substance P-saporin group, n = 8). To detect dorsal root ganglion neurons innervating the L5/6 intervertebral disc, neurotracer (fluoro-gold crystals) was placed into the intervertebral disc. Seven days after fluoro-gold application, the L5/6 intervertebral disc was exposed and injected with 175 ng of sterile substance P-saporin (substance P-saporin group, n = 8). Fourteen days after the first operation, each dorsal root ganglion was harvested, sectioned, and processed for neurokinin-1 immunohistochemistry using rabbit antibody to neurokinin-1. The numbers of fluoro-gold labeled neurons, and fluoro-gold labeled and neurokinin-1 immunoreactive neurons were counted in both groups.Results. Neurons innervating the L5/6 intervertebral discs, retrogradely labeled with fluoro-gold, were distributed throughout dorsal root ganglions from L1 to L6 in both groups. Of fluoro-gold labeled neurons, the proportion of neurokinin-1 immunoreactive neurons was 35% in the control group. However, the proportion of neurokinin-1 immunoreactive neurons was 8% after administration of substance P-saporin into the intervertebral discs (substance P-saporin group). Substance P-saporin significantly decreased the ratio of neurokinin-1 immunoreactive neurons.Conclusion. Substance P-saporin decreased the ratio of neurokinin-1 immunoreactive neurons innervating the disc related to discogenic low back pain. Substance Psaporin may be a useful tool to investigate the mechanism of discogenic low back pain.